Saturn🪐🔭
Mars🔴⭐️
Venus🌋☁️
Neptune🔵💎
Pluto🌌💫
100

Saturn is primarily composed of these two elements, which are also the most abundant elements in the universe.

What are hydrogen and helium?

100

The Martian atmosphere is primarily composed of this gas, making up about 95% of it.

What is carbon dioxide?

100

Unlike most planets in the solar system, Venus rotates in this direction.

What is retrograde (or clockwise)?

100

This is the largest moon of Neptune, known for its retrograde orbit.

What is Triton?

100

Pluto has five known moons, with this being the largest.

What is Charon?

200

This scientist first observed Saturn's rings in 1610.

Who is Galileo Galilei?

200

The largest volcano in the solar system, located on Mars, is named this.

What is Olympus Mons?

200

This Soviet spacecraft became the first to successfully transmit data from the surface of Venus in 1970.

What is Venera 7?

200

This is the name of the largest storm ever observed on Neptune, comparable to Jupiter's Great Red Spot.

What is the Great Dark Spot?

200

This NASA spacecraft performed a historic flyby of Pluto in 2015, capturing detailed images.

What is New Horizons?

300

This icy moon of Saturn has geysers that eject water vapor and ice particles into space.

What is Enceladus?

300

This is the largest known impact crater on Mars, stretching over 2,000 kilometers in diameter.

What is the Hellas Basin or Hellas Planitia?

300

Venus has a very slow rotation period, taking about this many Earth days to complete one rotation.

What is 243 days?

300

This NASA spacecraft is the only one to have visited Neptune, in 1989.

What is Voyager 2?

300

This is a heart-shaped feature on Pluto that is partially submerged in large, bright glaciers of nitrogen ice. 

What is Sputnik Planitia?

400

One season on Saturn, such as summer or winter, lasts about this many Earth years.

What is 7.5 years?

400

Mars has two small moons, Phobos and this other moon named after the Greek word for fear.

What is Deimos?

400

This is the largest volcanic structure on Venus, stretching over 500 kilometers in diameter.

What is Maat Mons?

400

Neptune completes one rotation on its axis in about this many hours.

What is 16 hours?

400

The International Astronomical Union reclassified Pluto as a dwarf planet in this year.

What is 2006?

500

This NASA spacecraft, launched in 1997, spent 13 years studying Saturn and its system.

What is Cassini?

500

This enormous canyon system on Mars is over 4,000 kilometers long and up to 7 kilometers deep.

What is Valles Marineris?

500

This mountain range on Venus is the only surface feature on the planet named after a man.

What is Maxwell Montes?

500

Neptune takes this many Earth years to complete one orbit around the Sun.

What is 165 years?

500

Pluto's surface temperature is extremely cold, averaging around this many degrees Fahrenheit.

What is -375 degrees Fahrenheit?

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